Best overlap: 8:30 AM to 5:30 PM in Islamabad is 9:00 AM to 6:00 PM in Kolkata.
Target 8:30 AM to 5:30 PM in Islamabad, which lands at 9:00 AM to 6:00 PM for the Kolkata side. That's a roomy 9 hours of common time each day, so finding a slot that suits everyone is rarely a problem.
A complete guide to time zones in 2025, from UTC and GMT differences to Daylight Saving Time changes, IANA database rules, abbreviation pitfalls, and developer best practices for handling global time. -